1. Field of Invention
The present invention relates to a video device and a control method thereof and, more particularly, to a video device and a control method thereof which automatically set a copy control information (CCI) value when the CCI value related to content of an identical digital broadcasting channel is not received in channel conversion.
2. Description of the Related Art
Recently, digital terrestrial television broadcasting and digital satellite broadcasting have been started as broadcasting mediums have rapidly become digitized all over the world.
A digital cable broadcasting standard is classified as an OpenCable standard which is used in America and Korea and the like, a digital video broadcasting cable (DVB-C) standard which is used in Europe, and an integrated service digital broadcasting cable (ISDB-C) standard which is used in Japen.
Herein, the OpenCable standard is formed on the basis of a Moving Picture Exports Group-2 (MPEG-2) used as a video standard and a Data Over Cable Service Interface Specification (DOCSIS) used as a transmit standard of a cable modem. The OpenCable standard is a set of interface standards of a digital device like a Set Top Box of a digital television manufactured at Cable Television Laboratories, Inc., and definitions thereof.
The OpenCable standard separates a conditional access part from the Set Top Box. Therefore, to satisfy Federal Communications Commission (FCC) rules in the OpenCable standard, the existing Set Top Box consists of a video device (host) not having the conditional access part and a conditional view module (hereinafter referred to a Point Of Deployment, POD) including the conditional access part.
Hereinafter, a copy protection system that involves matching between the video device and the POD in the OpenCable standard will be described as follows. The OpenCable standard is embodied with two kinds of the anti-copy systems.
One is a Conditional Access System (CAS) with respect to a digital cable broadcasting sending system, and the other is a Copy Protection System (CPS) between the POD separated from the video device (host) and the video device. Generally, an anti-copy system means the CPS of the latter.
The existing digital broadcasting receiving device system has a function which receives coded content from the sending system and selectively restores the coded content into a common video, inside the receiving device, (i.e., an Imbedded Conditional Access system). The POD means a security module which separates a conditional access function from the receiving device.
In the CPS, the coded digital content, which is sent from a sending system, is decoded at the POD used as a subscriber receiving device, (i.e., a CA Payload Decryption) and is changed to the digital content of a plaintext situation. And then the content is again coded by the CPS standard (i.e., a CP Encryption), and the coded content is transported to the video device. With such a coding, the CPS restricts the digital content of the plaintext to being transported from the POD to the video device.
Such a CPS is applied to all kinds of content, but it does not mean that all kinds of content are necessarily coded and then transported to the video device. That is, the content to which the CPS is not applied, for example, can receive the public channel and only the charged digital content is protected from the copying.
The application standard of coding for the copy protection is preferentially given to a content maker manufacturing the appropriate content. The information, which determines whether the CPS is allowed or not, is referred to as a Copy Control Information (CCI) value, and the POD of the receiver receives the CCI value corresponding to the transported digital content. Herein, the sending system transports the message, which controls whether the receiver is allowed to contact the charged digital content or not, with a Private Section form to the MPEG-2 Transport Stream.
Therefore, the video device and the POD control whether the video device related to the digital content of the appropriate channel can be copied or not, through the CCI value exchange.
FIG. 1 illustrates an Encryption Mode Indicator (EMI) among the CCI value applied from the OpenCable standard. As shown therein, the content which is the CCI value of ‘00’ allows a copy free, and the content which is the CCI value of ‘01’ prevents the copying of two or more generations, and the content which is the CCI value of ‘10’ allows only the copy of one generation, and the content which is the CCI value of ‘11’ does not allow any copying.
FIG. 2 illustrates an exchange process of the CCI values between the video device and the POD in the OpenCable standard.
At operation S20, when a channel conversion request is received at the video device and then the channel is converted, at operation S21, the video device determines whether the converted channel is the digital broadcasting channel or not. At operation S26, when the converted channel is not a digital broadcasting channel, that is, when the converted channel is an analog broadcasting channel, the channel conversion is finished without the CCI value exchange.
Meanwhile, when the converted channel is a digital broadcasting channel, at operation S22, the POD transports a Request_CCI_Exchange to the video device. At operation S23, the video device receiving the Request_CCI_Exchange transports a Request_CCI_N_host to the POD in the response thereof.
At operation S24, in case where the Request CCI_N_host is received from the video device, the POD transports an Authentication CCI Message to the video device, and at operation S25, the video device determines the CCI value from the received Authentication CCI Message. Therefore, at operation S26, the channel conversion is finished. Accordingly, the video device controls whether the content of the appropriate digital broadcasting channel is copied or not, according to the CCI value.
Herein, when the CCI value of the appropriate digital broadcasting channel is not received at the video device in a process where the video device converts the channel into the digital broadcasting channel, the OpenCable standard requests that the video device set up the CCI value of the appropriate digital broadcasting channel as a ‘11’ value. That is, copying is not allowed when the content of the digital broadcasting channel of the video device does not receive the CCI value.
However, in the OpenCable standard environments, when the user converts the analog broadcasting channel into the digital broadcasting channel while viewing the analog broadcasting channel, there is a case that the CCI value exchange with respect to the appropriate digital broadcasting channel is not accomplished. Particularly, when the user converts the channel into the analog broadcasting channel while viewing the special digital broadcasting channel, and the user converts the channel into the former digital broadcasting channel, an error happens because the CCI value exchange is not accomplished.
Therefore, copying is restricted when the content which is copied freely, that is, the public content, is exchanged during the channel conversion.
Further, when the user recognizes that the content of the digital broadcasting channel is the content in which the copying is allowed, the user may misunderstand the copy error of the video device.